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Narrowband Color Mapper Script
I downloaded the NBCM script successfullly in the resource manager, quit Pixinsight, restarted and Pixinsight crashed. I quit and restarted again and could not find the script in utilities or anyplace else. And oddly, I could not find anything for this script on the PI Forum.
I have OS X 12.6.7 on a 2017 iMacPro.
Gary
Comments
I am assuming you would like some constructive feedback on NBColourMapper. The more I use it the better I like the ability to see changes on the screen as I edit swatches. But I’ve also generated a few questions.
1. I have some new information on the problem of having to double-click Update to install a swatch. I revised all the swatches of a palette to obtain a new configuration without adding and defining a new palette. I assumed I was just editing the old palette. The main changes were to saturation, which I changed in several instances from .5 to .75. My sequence was: Add swatch with + —> Select View —> Edit —> change saturation —> Update. The first click on Update installs the color in the top window, but a second click is needed to install the file ID.
2. I noticed that these revised changes were unstable over shutdowns and restarts. After shutting off the computer and returning a day later, half my changes had reverted to the palette previously defined. What, exactly, does one have to do to ensure changes are saved? I’m just guessing that one must define a new palette for each change in a palette.
The following points pertain to RGB files created with NBCM from six JWST CEERS filter images. The filter images are from Pointing #6, panel A, at this LINK.
3. With a freshly combined and color calibrated non-linear RGB file, I find it almost impossible to use GeneralizedHyperbolicStretch to increase contrast in brighter galaxies. A click in the Realtime Preview window sends the yellow vertical line almost to the right edge of the histogram window and the sliders are not very functional. Could it be that combining six files results in too many bright pixels? The galaxies have centers that are too bright (see attachments), so I will experiment with dropping or suppressing files. Does using a mask that protects the background create a problem? I have been using a luminence mask.
4. A new linear color calibrated (or not) RGB file seems to work well with NoiseExterminator and an inverted-luminance mask, but not with BlurExterminator and a luminance mask. That is, the Realtime Preview window shows no desirable effect, and in fact little effect at all with or without a mask. The same is also true of MultiscaleMedianTransform and ColorSaturation.
5. I have tried to be attentive to the backgrounds. I notice that my backgrounds always end up quite dark, generally as a result of trying to balance colors and obtain optimally sharp detail in the galaxies. Is there a suggestion on how I might obtain a little more visible background and still preserve these virtues? I am not entirely convinced that more visible background would be a good thing, because the galaxies in the background are so tiny that they might blur out.
"As an example, we can confidently state that noise reduction (of any sort) should not be applied before deconvolution (of any sort). Noise reduction tends to destroy the low-contrast information at fine scales that deconvolution needs to function well, and it gives the deconvolution algorithm a false sense of the signal-to-noise ratio in the image. Applying deconvolution after noise reduction may produce an image that “looks sharper,” but the accuracy of those sharper details would be highly questionable."